Combination warm and cool mist humidifier

ABSTRACT

A humidifier includes a housing with a substantially open top portion. Water can be added to the humidifier by pouring the water into a water reservoir through an open top. The water is pumped from the water reservoir to an upper portion of the humidifier where it is dispersed into the environment by a flow of air. The humidifier may include both an ultrasonic nebulizer and a heater to provide a warm mix of cool mist and hot vapor. Alternatively, a warm mist can be provided by dispersed water from an ultrasonic nebulizer in combination with warm air. The humidifier may also solely provide a cool mist from an ultrasonic element, or the water can be dispersed using a wicking filter.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/229,133, filed Jul. 28, 2009, which is incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates generally to humidifying devices, and morespecifically to humidifying devices with an open top through which atank may be filled with water.

BACKGROUND OF THE INVENTION

Portable humidifying devices, or humidifiers, are used to moisturize theambient air in a room, most commonly, a single room of a home. Differenttypes of humidifiers are available in both the warm and cool mistvarieties. Evaporative humidifiers, or wick humidifiers, utilize areservoir of water, from which the wick draws moisture, and a fan whichforces air through and/or past the wick, thereby picking up moisture asthe air is directed through a spout or vent into the room. Ultrasonichumidifiers utilize nebulizers or ultrasonic transducers, a metaldiaphragm vibrating at ultrasonic frequency, to cause a fog or mistformed of small water droplets to rise from the surface of a reservoircontaining the transducer and out of a directed opening into the room.Similarly, impeller humidifiers break water into small droplets througha rotating disc that directs the water through a diffuser. Becauseevaporative, ultrasonic and impeller humidifiers do not heat the water,they are commonly referred to as cool mist humidifiers.

Vaporizers or steam humidifiers boil water and release the steam througha spout or vent into the room. However, due to the high temperatures ofthe steam (>100° C.), it is usually cooled somewhat before beingreleased into the room. Typically, this is done by mixing it withcooling air from a fan to create a warm mist that is safe to users. Thecooling air is usually mixed with the steam in a pathway leading to thedirected opening into the room to ensure that it is sufficiently mixedand contains no “hot spots.” The smaller the opening into the room, themore it is mixed and the safer the resultant warm mist. Such so-called“warm mist” humidifiers do not produce a true warm mist because thesteam is mixed with cooling air that is not humidified, reducing bothoutput and efficiency. To increase output, the steam is superheated,thus further increasing the risk of getting burned.

However, humidifiers having a combination of warm and cool mist do nottypically boil the water. Rather, these combination humidifiers merelyheat the water, usually in a connecting tube extending to the nebulizer.

Warm mist humidifiers, though typically consuming more power, alsopurify the mist through boiling to kill bacteria in the water, whilecool mist humidifiers must be cleaned regularly to prevent theaccumulation of bacteria and contamination of the air caused by theprojection of said bacteria with the mist. Regardless of type, mosthumidifiers utilize a removable and fillable water tank and a housingwith a directed opening, or output vent, which serves to mix andconcentrate the mist into the room such that it is projected withsufficient velocity for the droplets to spread apart and humidify alarger volume of the air in the room, not just the air near thehumidifier.

SUMMARY OF THE INVENTION

Creating a “true warm mist” through the combination of cool mist andsteam, or warm mist, increases efficiency and output since the steam isnot mixed only with relatively dry cooling air, but also with cool mistcreated by an ultrasonic transducer. The mist should sufficiently mix toachieve a substantially uniform, safe temperature. While forcing themist through a small directed opening or vent is an effective mixingmechanism, spreading the mist through a large open top portion of thehumidifier while maintaining a high output is more aesthetic (creating aspa look and feel) and distributes the mist evenly into a larger area ofthe room. Because nebulized mist does not rise as steam does, a mixingplenum in combination with air flow facilitates a fuller mixing, andtherefore a more “true warm mist,” before rising through the open topportion. Moreover, because constantly removing and replacing a watertank for refilling can become rather arduous, a humidifier which isfillable by merely pouring water into an open top portion makes thehumidifier more convenient to use.

In an embodiment, the present invention provides a combination warm andcool mist humidifier having a housing with a substantially open topportion. The housing has an inner wall and an outer wall and an air gapbetween the inner and outer walls. Each of the inner and outer wallsincludes at least one vent. A main water reservoir within the housing isfillable by providing water to the substantially open top portion. Alevel engine deck is disposed above a bottom of the main water reservoirand an impeller is configured to pump water from the main waterreservoir to an overflow chamber of the engine deck. The engine deckincludes a heating reservoir having at least one heating elementdisposed therein and a nebulizing chamber having at least one ultrasonictransducer disposed therein. An engine chamber is disposed adjacent thewater reservoir and below the engine deck and includes at least onemotor for driving the impeller and a fan disposed adjacent the at leastone vent of the outer wall of the housing so as to draw air into the airgap and through the at least one vent of the inner wall of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will be morereadily apparent from the following detailed description and drawings ofillustrative embodiments of the invention in which:

FIG. 1 is a perspective view of a humidifier in accordance with anembodiment of the present invention showing the components of the enginedeck;

FIG. 2 is a perspective view of a humidifier in accordance with theembodiment of FIG. 1 showing a shield over the engine deck;

FIG. 3 is a top view of the interior of a humidifier in accordance withthe embodiment of FIG. 1;

FIG. 4 is a sectional view of the humidifier of FIG. 2 taken along lineA-A;

FIG. 5 is a perspective view of a humidifier in accordance with anembodiment of the present invention including a baffled cover;

FIG. 6 is a schematic representation of another embodiment of ahumidifier;

FIG. 7 is a cross-sectional side view of another embodiment of ahumidifier;

FIG. 8 is a front view of the humidifier of FIG. 7

FIG. 9 is a cross-sectional front view of the humidifier of FIG. 7;

FIGS. 10-12 illustrate various weep hole configurations in accordancewith an embodiment of the invention;

FIG. 13 is a top view of another embodiment of a humidifier;

FIG. 14 is a cross-sectional side view of the humidifier of FIG. 13; and

FIG. 15 is a cross-sectional front view of the humidifier of FIG. 13.

Like reference numerals are used in the drawing Figures to connote likecomponents of the humidifier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a humidifier 10 in accordance with an embodiment ofthe invention has a substantially rectangular housing 100 with asubstantially open top portion 128. The main water reservoir 12 of thehumidifier 10 is disposed within the housing 100 below the open topportion such that the water reservoir 12 is open to the atmosphere atthe top. Accordingly, the humidifier 10 may be top-filled to providewater to the main water reservoir 12. A groove 14 in the bottom 13 ofthe water reservoir 12 provides water to an impeller 16 which draws thewater up through a tube 18 to an overflow chamber 22 of a substantiallylevel engine deck 20 (FIGS. 3 and 4). The overflow chamber 22 maintainsthe level of water at the engine deck 20 by allowing excess water toflow back into the water reservoir 12 via an overflow opening 24.Additionally, the overflow chamber 22 may also demineralize the waterfor a cleaner operation, for example, by providing a filter or achemical for demineralization in the overflow chamber 22. From theoverflow chamber 22, the water flows through a first path 26 to aheating reservoir 30 where a heating element 32 boils the watercontained therein. From the heating reservoir 30, the water then flowsto a nebulizing chamber 40 via a second path 36. The nebulizing chamber40 includes an ultrasonic transducer 42 for providing a cool mist. Anadditional path extending from the nebulizing chamber 40 to the mainwater reservoir 12 may also be provided as a return path. In analternative embodiment, the water may flow from the overflow chamber 22to each of the heating reservoir 30 and nebulizing chamber 40 directly.In such an embodiment, the flow can be controlled such that waterflowing back into the water reservoir 12 is not heated.

Referring to FIGS. 1-4, the engine deck 20 is provided above andadjacent to the main water reservoir 12 with a sidewall 44 extendingupward from the bottom of the main water reservoir 12 to the engine deck20. The sidewall 44 also serves to insulate an engine chamber 118contained within the housing 100 adjacent the main water reservoir 12and below the engine deck 20. The sidewall 44 may be inclined towardmain water reservoir 12 to help direct any overflow water and may alsoinclude a recessed portion for the impeller 16. This inclined sidewall44 can reduce or eliminate sounds generated by splashing and dripping asthe water returns to the water reservoir 12. Preferably, the housing 100includes at least an outer wall 102 and an inner wall 104 with an airgap 106 defined therebetween. The inner wall 104 is attached or integralto the engine deck 20 such that the engine chamber 118 has pathways tothe air gap 106. The engine chamber 118 is sealed within the housing 100from the main water reservoir 12 and the engine deck 20 so as to preventwater from entering into the engine chamber 118. Preferably, the air gap106 is provided along all four sides of the housing 100. In oneembodiment, the air gap 106 is also provided in the base section of thehousing 100 extending below the main water reservoir 12.

At least one motor 120 is provided in the engine chamber 118. The motor120 preferably utilizes a magnetic drive with first and second outputshafts 122, 124 at opposite sides thereof. In this manner, the impeller16 can be attached to the first output shaft 122 and a fan 126 can beattached to the second shaft 124 so as to drive both the impeller 16 andthe fan 126 by the same motor 120. Preferably, the first output shaft122 runs to drive a first magnet 123 disposed within the engine chamber118. The first magnet 123 is coupled to drive a second magnet 125disposed on the other side of sidewall 44. The second magnet 125 isconnected to the impeller 16 so as to drive it. The magnetic coupling ofthe first and second magnets 123, 125 also serves to maintain theimpeller 16 on a bearing 121 which prevents the impeller 16 frombecoming unstable and causing noise when the main water reservoir 12reaches a low fill level. The magnetic coupling also ensures that noopening to the engine chamber 118 is created through which a leak couldform. Such an arrangement saves space, increases efficiency anddecreases manufacturing costs since only one motor 120 is required.However, it is also possible for the fan 126 and the impeller 16 to beseparately driven. The fan 126 also serves to cool the engine chamber118, including motor 120 so that it operates more efficiently and doesnot overheat.

The fan 126 is arranged adjacent the outer wall 102 of the housing 100in a region containing intake vents 108. The intake vents 108 may beprovided with a filter to purify the air as it enters the housing 100.The motor 120 drives the fan 126 in order to pressurize the enginechamber 118 and force air into the air gap 106. The air travels betweenthe outer and inner walls 102, 104 of the housing 100 (i.e., through airgap 106) and exits into the interior of the humidifier 10 through one ormore output vents 110 disposed in the inner wall 104. Preferably, outputvents 110 are provided in the inner wall 104 on each side of the housing100 at the open top portion 128, or between the engine deck 20 and theopen top portion 128, in order to mix and evenly distribute the warmmist rising from the heating reservoir 30 and cool mist rising from thenebulizing chamber 40. The airflow provided by the output vents 110 alsoserves to pressurize the interior of the humidifier 10 so that thecombined mist rises substantially uniformly from the open top portion128. In this manner, a substantially uniform output of mist at asubstantially uniform temperature is provided throughout the open topportion 128 of the humidifier 10. Preferably, the temperature of the airand combined mist exiting through the open top portion 128 is in therange of 110° F. to 130° F. (43.3° C. to 54.4° C.).

The engine deck 20 is covered by a shield 116 to prevent water fromfalling onto the engine deck when the humidifier 10 is top filled by auser. Preferably, the shield 116 is inclined downward from the innerwall 104 at the rear of the housing 100 toward the main water reservoir12. The shield 116 may be a single sloped surface or a series of slopedsteps and extends at least slightly beyond the sidewall 44. The shield116 may be attached to the housing 100, but is more preferably removablyarranged on supports 114 to allow access to the engine deck. In theembodiment shown in FIGS. 1-4, the shield 116 includes sloped steps withair gaps between the steps to allow the mist to pass therethrough. Forthis reason, output vents 110 are provided behind the steps between theengine deck 20 and the shield 116. The humidifier 10 can be top filledwith water anywhere through the open top portion 128 and the shield 116directs the water away from the engine deck 20 and into the main waterreservoir 12. Accordingly, the humidifier 10 is easy to fill withoutaffecting its operation as a substantially even level of water at theengine deck is maintained. In conjunction with the airflow from theoutput vents 110, the shield 116 also helps to direct condensationforming on the bottom thereof away from the engine deck 20. In addition,the bottom of the shield 116 may also include ribs to direct water andprevent condensation from falling into the heating reservoir 30 or thenebulizing chamber 40.

The main water reservoir 12 includes a shut-off device 48 which may be,for example, a hollow tube 50 having a floating foam donut 52 disposedthereabout. The hollow tube 50 includes a thin metal magnetic reedswitch 54 disposed at a predetermined minimum fill level at or near thebottom of the main water reservoir 12. As water in the main waterreservoir 12 is used up, the donut 52, which also contains a magnet,floats downwards with the level of water toward the reed switch 54. Uponreaching the reed switch 54, the magnet in the donut 52 shuts off thereed switch 54 which is connected to the power supply of the humidifier10 to prevent the heating element 32 from burning out. In addition tocutting off power to the humidifier 10, the reed switch may also be usedto cause an indicator light 140 on the housing 100 to be lit and toindicate that the unit is out of water. Further, additional reedswitches 54 may also be provided at predetermined heights in the hollowtube 50 to indicate one or more fill levels. As the main water reservoir12 is filled, the donut 52 will float upwards toward a reed switch 54and, upon reaching one of the predetermined heights, will turn on thereed switch 54 which is connected to an indicator light 140 on thehousing 100 to indicate to a user that a fill level (for example, amaximum fill level) has been achieved so that the humidifier 10 is notoverfilled. Alternatively, a low voltage system with small electrodesmay be substituted for the reed switches 54. In such an embodiment, acircuit can be completed by water contacting the electrodes therebycausing the indicator light 140 to indicate to the user that a desiredfill level has been achieved. As another alternative, or in addition,the humidifier may include a float switch to shut off the humidifierwhen it is empty.

Alternatively or in addition, one or more shut-off devices could beprovided on the engine deck 20. Accordingly, such a shut off devicecould directly measure the amount of water being received by either orboth of the heating element 32 or ultrasonic element 42. Thus, thevaporizing engines could be shut off if they are not receiving water,regardless of the amount of water in the tank (for example, if therewere a problem with the impeller 16).

Other fill level indicators, such as a viewing window in the housing 100with graduations, may also or alternatively be provided to indicate theoverall level of water in the main water reservoir 12. Likewise, atleast a portion of the walls of the housing 100 could be transparent andcould be provided with cascading water falling to the level of water inthe main water reservoir 12 so as to create a water wall effect.

The housing 100 may be any of a number of shapes, such as square,circular or oval and may be formed from one or more of plastic or metal.The base of the housing 100 may be provided with feet 129, which mayalso be adjustable in height, to keep the humidifier 10 stable andlevel. Additionally, a decorative wall or covering with various patternsand colors may be provided around the outside of the housing 100.Further, the housing 100 may include lighting, for example,light-emitting diodes (LEDs) within the humidifier 10 or about the opentop portion 128 to accent or “light up” the rising mist in variouscolors. Where LEDs are provided, it is possible to also shunt the airprovided across the nebulizing chamber 40 so as to create a swirlingglow effect.

While it is preferable to arrange the main water reservoir 12 on oneside of the housing 100 and the engine chamber 118 on the other in orderto efficiently make use of the internal space of the humidifier 10,other conFigurations are also possible. For example, the engine chamber118, with the engine deck 20 disposed thereabove, could be sealingly,centrally disposed in the housing 100, with the main water reservoir 12surrounding the engine deck 118. To draw air into the housing 100, adrive shaft could be attached the first output shaft 122 extendingthrough or beneath the main water reservoir 12 to a fan 126 disposed ina widened region of the air gap 106 adjacent intake vents 108.

The impeller 16 may be continuously or periodically operated to providewater to the engine deck 20 through tube 18. Preferably, the impeller 16and the fan 126 are both continuously run by the motor 120.Additionally, by providing a continuous supply of water at highervolumes to the overflow chamber 22, a waterfall effect through theoverflow opening 24 and/or overflow spout 23 can be achieved. Theoverflow chamber 22 preferably demineralizes the water, for example, byproviding one or more filters disposed between ribs at an inlet and/oran outlet of the overflow chamber 22.

Because the engine deck 20 is substantially horizontally level and theoverflow chamber 22, the heating reservoir 30, the nebulizing chamber 40and the first and second paths 26, 36 are formed as recesses therein,the water is provided at substantially the same level to the foregoingcomponents of the engine deck 20 to facilitate a level, controlled rateof flow. Instead of recesses, the first and second paths 26, 36 mayalternatively be tubes or other types of passages. From the overflowchamber 22, the water flows through the first path 26 to the heatingreservoir 30. The heating reservoir 30 includes at least one heatingelement 32, for example, a centrally disposed, traditional resistanceheating element, which boils the water in the heating reservoir 30. Thefirst path 26 is preferably a tortuous or serpentine path so as to tunethe flow of water to the heating reservoir 30. Similarly, the secondpath 36 extending from the heating reservoir 30 to the nebulizingchamber 40 is also preferably a tortuous or serpentine path to controlthe flow rate and to cool the water before it reaches the nebulizingchamber 40. Due to a relatively small cross sectional area of the firstand second paths 26, 36 relative to the heating reservoir 30 and thecontrolled flow of the water provided by the tortuous or serpentinepath, the convective losses from the heating reservoir 30 are reduced,and thus, boiling efficiency is increased. In conjunction with the tunedflow of water from the first path 26, the heating reservoir 30 is ableto consistently produce a high output of steam. A high output ofhumidifying mist is produced by the humidifier 10 when the high outputof steam is mixed with the cool mist emitted from the nebulizing chamber40 by the at least one ultrasonic transducer 42 vibrating therein atultrasonic frequencies. The arrangement of the heating reservoir 30 andthe nebulizing chamber 40 on the engine deck 20 (as illustrated, forexample in FIG. 1) could be switched, so that the water reaches thenebulizing chamber 40 before it reaches the heating reservoir 30. Whencooler water is provided to a nebulizer the mist can have the tendencyto condense onto a cool floor. Moreover, because the water is purifiedby boiling in the heating reservoir 30 (killing approximately 96% of thebacteria) both the warm and cool mist are purified and the bacteria isprevented from becoming suspended in the ambient air. Nevertheless, itis possible to provide water to the nebulizing chamber 40 directly fromthe overflow chamber 22, in particular in a cool mist embodiment wherethe heating reservoir 30 is not provided. Likewise, water could also beprovided directly to the heating reservoir 30 as well. Alternatively, asdescribed above, two separate paths could extend from the tube 18 alongthe engine deck 20 to the heating element 32 and ultrasonic element 42.Accordingly, the warm mist from the heating element 32 and cool mistfrom the nebulizer 42 would mix before exiting the humidifier 10.

The humidifier 10 may also utilize ultraviolet disinfection to make thewater germ-free. One way to accomplish this would be to provide anultraviolet lamp adjacent to the first path 26. Other methods ofproviding ultraviolet disinfection are described in the commonly ownedU.S. Pat. No. 7,513,486, the entire contents of which is incorporatedherein by reference.

In one embodiment, the heating element 32, the ultrasonic transducer 42and the motor 120 are connected to the same standard power supply, buthave separate controls for each on a controller 130 connected to a powersupply PS, for example, a battery or a standard AC source through astandard power cord 138. For example, a transducer control 132, aheating element control 134 and a fan speed control 136 may be providedto separately control the ultrasonic transducer 42, the heating element32 and the fan 126, respectively. In this way, it is possible for theuser to get only cool mist from the nebulizing chamber 40 or to get onlywarm mist from the heating reservoir 30. Additionally, the temperatureof the combined mist may be adjusted by varying the power levelsprovided to the heating element 32, the ultrasonic transducer 42, and/orthe fan 126. Further, a temperature sensor 150 may be provided andcoupled with the controller 130 to automatically provide the properpower levels at all times. A humidity sensor 152 may be provided near orat the open top portion 128 and/or outside the housing 100 to sense thelevel of humidity and send a signal to the controller 130 to throttleback the power levels when it nears a predetermined humidity level. Inthis way, it is possible to avoid the non-uniform on/off cycling oftypical humidifying devices. The controller 130 may be aproportional-integral-derivative (PID) controller communicating with thehumidity sensor 152 and/or temperature sensor 150 and using control loopfeedback that throttles back power to substantially maintain apredetermined humidity level and/or temperature.

In other embodiments, different models or conFigurations of thehumidifier 10 are provided. For example, the engine deck 20 may containeither the heating reservoir 30 only or the nebulizing chamber 40 onlyto provide warm mist or ultrasonic/cool mist models, respectively. Inthese cases, the overflow chamber 22 would extend via a first path 26 toeither the heating reservoir 30 or the nebulizing chamber 40, dependingon the model, and a second path could lead back to the main waterreservoir 12. The humidifier 10, including the combined mist, the warmmist and ultrasonic/cool mist models, may also be provided with anevaporative wicking filter and/or as an evaporative model.

To provide such an evaporative model, a wicking filter 162 (shown forexemplary purposes in FIG. 1 with dashed lines) having a supportinggrill 160 is provided on the engine deck 20 over the overflow chamber22, or a separate reservoir, to draw water therefrom. The wicking filter162 is typically formed from slit and expanded paper provided inmultiple layers. Air is then forced orthogonally through or past thewicking filter 162 from the pressurized engine chamber 118 throughoutput vents 110 provided in the engine deck 20 below the wicking filter162 and/or on the inner wall 104 of the housing 100. Alternatively, theairflow may be reversed such that it is drawn into the humidifierthrough the wicking filter 162. Preferably, the wicking filter isarranged horizontally or at an incline relative to the engine deck 20 soas to maximize its surface area facing the substantially open topportion 128. In this arrangement, the wicking filter 162 pulls water inhorizontally through its layers from the overflow chamber 22 and/or oneor more additional chambers. A gutter 161 may be provided around theperiphery of the wicking filter 162 to direct water dripping therefromback to the main water reservoir 12, and the wicking filter 162 may beinclined toward the gutter 161. Providing moisture to at least a portionof the cooling air through the wicking filter 162 further provides theadvantage of increased humidity levels which can be attained. Inaddition, a purely evaporative model of the humidifier 10 could beprovided by leaving out the heating chamber 30, the nebulizing chamber40 and first and second paths 26, 36 or by shutting them down via theheating element control 134 and the transducer control 132.

Referring to FIG. 5, a cover 60 which may also serve as a mixing plenum61 is provided at the open top portion 128 of the humidifier 10. Thecover 60 is preferably removable and supported by a ledge 112 at or nearthe top of the housing 100 (as shown, for example in FIG. 1). The cover60 includes a plurality of openings or baffles 62 throughout, forexample, in a grid pattern. The baffles 62 may be of various size andshape, such as rectangular or circular. The baffles 62 and the cover 60facilitate a more uniform flow of mist through the open top portion 128by further spreading and mixing the warm and cool mist and providingdirected openings for the combined mist. The cover 60 may also includespouts and/or paths which may be, e.g., aqueduct paths for retainingwater on the surface thereof. Preferably, a mixing plenum 61, which mayhave a similar conFiguration to the cover 60, or could consist of othershapes, such as tapered, and may include a plurality of spouts and/ortortuous paths, is also provided below the cover 60 for further mixingthe cool mist and steam prior to it rising out from the top of thehumidifier 10. Additionally, the cover 60 provides a support surface forvarious additional features for aesthetics and/or increasedfunctionality. For example, a bed of smoothed stones 64, or polishedpebbles, may be provided on the cover 60. In addition to making thehumidifier more aesthetically pleasing by giving a natural spa-like lookand feel, the smoothed stones 64 also serve multiple functions. First,the stones 64 help to further mix and distribute the warm mist as ittravels through the stones 64 and out of the top of the humidifier 10.Second, the stones 64 are warmed and wetted as mist rises therethrough(and also wetted when the humidifier 10 is top filled by the user),thereby providing additional heat and moisture to the rising mistthrough convection and evaporation. Additionally, the stones 64 may beprovided with an aromatic oil to provide a pleasing and fragrance to theroom. Further, a medicated inhalant may also be provided at the cover 60for therapeutic purposes. The open top portion 128 and the evendistribution of mist at a substantially uniform and safe temperaturemakes it easy for a user to utilize the humidifier 10 for therapeuticpurposes since it creates a larger area for the user to breathe in themedicated inhalant without fear of being burned. Similarly, wood chips,pellets or blocks could also be provided on the cover 60 serving likefunctions to the stones 64.

FIG. 6 shows a schematic illustration of another embodiment of ahumidifier 200 in accordance. Humidifier 200 illustrates additionalfeatures of a humidifier that may be implemented in accordance with theinvention. These features can be combined with any of the featuresdescribed above with respect to humidifier 10. Humidifier 200 includes awater feature 202, in the form of a shallow waterfall. The water feature202 is an attractive addition of the humidifier 200 and functionallydelivers water pumped from the main water reservoir 212 to the enginedeck 220. The water feature 202 may include one or more steps 204 thatthe water cascades over as it flows down the water feature. The water ispumped up to the water feature 202 from the main water reservoir 212with an impeller 216. The impeller 216 is driven by a motor and may beconnected thereto magnetically as discussed above with respect tohumidifier 10. Although the impeller 216 and fan 226 are shown atopposite sides of humidifier 200, these elements may be conFigured moreclosely so that they can be driven by a single motor, as discussedabove. In operation, the water is driven up to the water feature 202through a tube 218, as shown by the solid arrows in FIG. 6. The waterthen flows down the water feature 202 until it falls into an overflowchamber 222 on the engine deck 220. The engine deck 220 is equipped witha nebulizing chamber 240, which receives water from the overflow chamber222. An ultrasonic transducer 242 disperses water from the nebulizingchamber 240 into the air above engine deck 220 forming a cool mist.Excess water that is not immediately converted into a mist falls fromthe overflow chamber 222 back into the main water reservoir 212.

Use of the impeller 216 to cycle water over the water feature 202 andonto the engine deck 220 where it contacts the ultrasonic transducer 242allows the main water reservoir 212 to be open to atmospheric pressure.In contrast, the water in most humidifier tanks is held in the tank by avacuum. This open type of system also allows the amount of water held inthe nebulizing chamber 240 to be controlled very precisely by using theoverflow chamber 222 to distribute excess water back to the main waterreservoir 212 so that the ultrasonic transducer 242 always has anappropriate amount of water.

The cool mist formed by the ultrasonic transducer 242 is mixed with airin a mixing chamber 230 above the engine deck 220. The air is deliveredto the mixing chamber 230 from a duct 232 as the result of a fan 226disposed in an engine chamber 208 below the engine deck 220. The fan 226pressurizes the air in the mixing chamber 230, causing it to flow up andout of the humidifier 200 through a cover and stones 214.

The humidifier 200 may be operated in the above-described manner toproduce humidification in the form of a cool mist. Alternatively, aheating element 234 may be included in the duct 232 to warm the airbefore it is mixed with the mist. As a result, the heated air heats thedispersed water producing a warm mist. The warm mist then rises throughthe cover 206 and stones 214 creating a spa effect. In the illustratedembodiment, the heating element is formed as a wire heater that is woundhelically within the duct between the fan 226 mixing chamber 230.Alternatively, the wire heater could be wrapped around the duct 232.Other embodiments of the heating element are also possible. For example,the heating element 234 may be a PTC element. The heating element 234could also be coupled to a heat exchanger to increase the efficiency ofthe delivery of heat to the air. Forming a warm mist by heating the airand mixing the heated air with the cool mist provides certain advantagesover the inclusion of a water heater in the humidifier. First, energyfrom the water heater can transfer to water outside of the heaterchamber. Thus, with a water heater, the water in the overflow chamber222 may be warmed. As a result, this warm water can overflow into themain water reservoir 212. Thus, over time, all of the water in thesystem can be warmed, which may be seen as disadvantageous by a user.Moreover, many ultrasonic transducers perform more efficiently withroom-temperature water. Thus, heated water will negatively affect theefficiency of the humidifier.

FIGS. 7-9 show another embodiment of a humidifier 300 in accordance withthe invention. Humidifier 300 illustrates additional features of theinvention, which may be combined with any of the features of humidifiers10 or 200. Similar to humidifiers 10 and 200, humidifier 300 includes anopen top 328 which allows the main water reservoir 312 to be filled bypouring water into the humidifier 300 from the top, for example, using apitcher. From the main water reservoir 312, the water is pumped upthrough a tube 318 to an overflow reservoir including a nebulizingchamber 340 on the engine deck 320. The water is pumped to the enginedeck 320 using an impeller 316, which is driven by a motor 314.

The engine deck 320 includes a nebulizing chamber 340 in fluidcommunication with an ultrasonic transducer 342. The transducer 342disperses water from the nebulizing chamber 340 into a cool mist in amixing chamber 330. The mist is then mixed with pressurized air that isdriven into the mixing chamber 330 by a fan 326. In the illustratedembodiment, the fan is housed in an engine chamber 308 disposed belowthe engine deck 320. The fan 326 is driven by a motor which may be thesame motor 314 as that which drives the impeller 316. Alternatively, aseparate motor may be used to drive the fan 326. The fan 326 pressurizesair within the engine chamber 308 which drives the air through a duct332 into the mixing chamber 330 where it mixes with the mist. As analternative, air may flow from the engine chamber 308 to the mixingchamber 330 through a port connecting the two chambers. The mist ispropelled into the atmosphere by the pressurized air within the mixingchamber 330 through a nozzle 306. In an embodiment, the nozzle may berotatable, such that the mist can be directed in a direction as desiredby the user.

Excess water pumped to the engine deck 320 overflows from the overflowchamber 340 down a water feature 302 back into the main water reservoir312. The water feature 302 of humidifier 300 is conFigured as a curvedslope that flows down to the main water reservoir 312. The slope 302curves downward, such that the gradient is shallow at the top and steepat the bottom. The bottom of the slope 302 flows into a funnel 324 thatdelivers the water back to the main water reservoir 312. The combinationof the slope 302 and the funnel 324 allows the water overflowing fromthe engine deck 320 to first flow smoothly into a pool formed in thefunnel 324 and then be poured into the main water reservoir 312. Thebottom of the funnel 324 has a constricted outlet 348, which controlsthe flow rate to the main reservoir 312. Accordingly, a pool of water isformed in the bottom of the funnel 324. The curved slope 302 of thewater feature allows the water to flow into the pool in the funnel 324quietly. This prevents a loud splashing sound that would otherwise occurif the water flowed directly into the water reservoir 312 from theoverflow chamber 322. The bottom of the funnel 324 may be positioned lowenough that constricted outlet 348 is submersed in the water within thereservoir 312, or it may be close enough to a surface that a splashingsound is avoided. The constricted outlet 348 may be achieved by a narrowtapering toward the bottom of the funnel 324 or with one or more smallopenings at the bottom of the funnel.

To prevent the funnel 324 from overflowing, it may include weep holes350 along a sidewall thereof. The weep holes 350 allow water to drainout of the funnel 324 when the water flow is greater than the amountthat can flow through the constricted entrance. Moreover, the weep holes350 can control the position of the top of the pool within the funnel324 over a range of different water flow rates. Within a range of flowrates, the water level within the funnel 324 will build until water isflowing out of the weep holes 350. Accordingly, the weep holes 350 canbe positioned at a height that is optimal for reducing splashing noisesof the water flowing down the curved slope 302.

To add further control to the water level in the funnel 324, a pluralityof rows 352 of weep holes may be included in the funnel at differentheights. In the illustrated embodiment, the weep holes increase in sizefrom the lowest row to the highest row, as shown in FIG. 10. This allowsgreater use of the weep holes 350 for draining water from the funnel324, as the water flow rate increases more drastically. The top row 352of weep holes may be large enough that water will flow out of the funnel324 at even very large flow rates. For example, if a user poursadditional water into the humidifier 300 on the curved slope 302.Further, the top row 352 of weep holes may include more holes than thelower rows. For example, in FIG. 10, each row contains one more weephole than the row below it. In the embodiment shown in FIGS. 8 and 10,the weep holes are all round. Alternatively, the weep holes may beformed in other shapes, such as ovals or polygons, as shown in FIG. 11.Moreover, the holes may all be formed in the same shape, as shown inFIG. 10, or they may have different shapes, as shown in FIG. 11.Furthermore, the holes may be bored through the side wall of the funnelin a variety of manners to vary the ease of manufacturing or the abilityof the holes to drain the water quietly down the side wall of the funnel324 which is slightly inclined toward the water reservoir. For example,FIG. 12 shows weep holes formed in three different manners. The image onthe left shows weep holes that are directed straight through side walls,which simplifies manufacturing. The image in the middle of FIG. 12,shows weep holes with a curved lower edge on the outer side of thefunnel 324. This would provide exceptionally quiet drainage through theholes. The image on the right shows angled weep holes which may be easyto manufacture and provide quiet drainage.

Humidifier 300 may also include a window 336 on a front surface thereof,as shown in FIG. 8 which allows the user to see the water level of themain water reservoir 312. A light may also be provided in the vicinityof the window 336 to illuminate the water level. In one embodiment, theconstricted outlet 348 may be aimed toward the window 336 within thewater reservoir 312. As a result, air bubbles that are introduced intothe water reservoir with water from the funnel 324 may travel to thewindow 336 and rise along the window creating a “water wall” visual thatis pleasing to the user.

FIGS. 13-15 illustrate another humidifier 400 in accordance with theinvention. Humidifier 400 illustrates additional features of theinvention, which may be combined with any of the features of humidifiers10, 200 or 300. Humidifier 400 includes a wicking filter 462 thatdisperses water into the air. A water feature 402 drips water onto thefilter 462, which is spread through the body of the filter. Air from afan 426 is forced up through the filter 426 to distribute the water intothe atmosphere around humidifier 400. The filter 462 may be formed fromone or more layers of paper or plastic sheet that is slit at regularintervals and expanded to provide a lattice structure with a largesurface area. Similar to humidifiers 10, 200 and 300, discussed above,humidifier 400 has an open top 428 so the water reservoir 412 may befilled by pouring water through the open top 428. The top of thehumidifier may include a grating 470 to protect the filter 462 fromobjects falling into the humidifier 400 and to encourage users to refillthe main water reservoir 412 from an open front side 454 of thehumidifier 400 that includes a funnel 424.

From the water reservoir 412, water is pumped to an upper portion of thehumidifier through a tube 418 using an impeller 416. At the top of thehumidifier 400, the water is guided to one end of a water feature 402 ata rear side 456 of the humidifier 400. The water flows through a channel404 across to the front side 454 of the humidifier dripping waterthrough a number of openings 410 in the channel 404 onto the wickingfilter 462. At the front side 454 of the humidifier, the water returnsto the water reservoir 412 via the funnel 424. Similar to that ofhumidifier 300, the water feature 402 may lead into the funnel 424 alonga curved slope so that a splashing noise is reduced. Moreover, funnel424 may have a constricted outlet 448 at the bottom to promote theformation of a pool in the funnel, which further silences the movementof the water.

As stated above, the water that is dripped onto the wicking filter 462is spread throughout the body of the filter which has a large surfacearea. From the wicking filter 462, the water is dispersed into theatmosphere by pressurized air within the humidifier 400 as a result ofthe operation of fan 426. The fan 426 is driven by a motor 414, which ishoused together with the fan 426 in an engine chamber 408. Air ispropelled by the fan 426 into the inside of the humidifier through avent 440. As pressure inside the humidifier builds, the air is forced upthrough the wicking filter 462, where it gathers moisture which is thendispersed into the room.

Similar to humidifier 300, humidifier 400 is configured to adapt tovarying amounts of water flow. Accordingly, the channel 404 of the waterfeature 402 includes dividers 430 that form three separate conduits inthe channel 404. The inner conduit includes one or more openings 410along its length to distribute a small amount of water to the wickingfilter 462 during low water flow levels. Accordingly, the humidifier 400is able to run for long periods of time when the water flow is low. Ifthe water flow is increased, the water will flow into the outerconduits, where it can be delivered by additional openings 410 to thewicking filter 462 over a larger area of the filter. To further limitthe output of the humidifier during low speed operation, the humidifier400 may include a louver in the air supply plenum to restrict air flowduring low speed operation. In such an embodiment, when the humidifierruns at high speed, the air pressure can force the louver to a fullyopen position. In contrast, when the humidifier runs at low speed, thelouver can be partially closed, thereby restricting air flow.

The wicking filter 462 is substantially planar and sits below thegrating 470 underneath the channel 404 of the water feature 402. Inoperation, the filter 462 is horizontally disposed so that the upwardmoving air passes through a large cross-section of the filter 462. Waterdripping down onto the center of the wicking filter 462 through theopenings 410 in the channel 404 is wicked horizontally outward so thatall of the air passing through the filter 462 is able to carry waterfrom the humidifier 400. The filter is supported in the humidifier by amesh support 460 that is configured as a thin sheet, such as a screen.Excess water that is not captured by the air flowing through the wickingfilter 462 will settle to the bottom of the filter 462 and dripdownward.

To control the dripping of the water from the wicking filter 462, themesh support 460 is stretched taut in the v-shape with the lowest point464 in the center. As a result, excess water in the filter will flow tothe center and drip in a controlled manner only from the low point 464of the filter. To utilize this controlled dripping, the humidifierincludes a conduit 474 disposed below the wicking filter 462 along thelow point 464 of the v-shaped support 460. To promote capturing of theexcess water in the conduit 474, the conduit 474 may include a centralridge 472 that extends up toward the support 460. The ridge 472 helpsbreak any surface tension in drops of water hanging down from the filter462, thereby ensuring that they fall into the conduit. Similar to thechannel 404 of the water feature, the conduit 472 may also have a curvedslope toward the front side 454 of the humidifier 400 forming a secondfunnel to quietly lead water into the reservoir. overbearing

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention. Accordingly, the invention is to be limited only by the scopeof the claims and their equivalents.

What is claimed is:
 1. A humidifier comprising: a housing with asubstantially open top portion; a main water reservoir tillable byproviding water through the substantially open top portion of thehousing; an engine deck configured to hold water disposed above a bottomof the main water reservoir; an impeller configured to pump water fromthe main water reservoir to an overflow chamber of the engine deck; aheating chamber disposed on the engine deck and having at least oneheating element disposed therein; a nebulizing chamber disposed on theengine deck and having at least one ultrasonic transducer disposedtherein; and an engine chamber disposed adjacent the main waterreservoir and below the engine deck, the engine chamber including atleast one motor for driving the impeller and a fan, the fan beingconfigured to draw air through the housing so as to carry water vaporproduced by the heater and nebulized air into the environment around thehumidifier.
 2. The humidifier of claim 1 wherein the engine deckincludes first and second paths configured to respectively direct waterfrom the impeller to the heating chamber and nebulizing chamber.
 3. Thehumidifier of claim 1 further comprising a control device operable toselectively operate the heating chamber and nebulizing chamber.
 4. Thehumidifier of claim 1 further comprising a control device operable toadjust the flow rate of the impeller.
 5. The humidifier of claim 1,wherein the housing includes an inner wall, an outer wall and an air gapbetween the inner and outer walls, the inner and outer walls includingat least one vent, and wherein the fun is disposed adjacent to the ventdisposed in the outer wall so as to draw air into the gap.
 6. Thehumidifier of claim 1, further comprising a cover disposed over the opentop portion configured to allow air and water to pass therethrough. 7.The humidifier of claim 6, further comprising stones disposed on thecover.
 8. The humidifier of claim 1, wherein the at least one motorincludes a motor having a magnetic drive coupled to the impeller.
 9. Thehumidifier of claim 8, wherein, the motor is also coupled to the fan.10. The humidifier of claim 1, wherein the overflow chamber includes anoverflow opening which is open to the main water reservoir.
 11. Thehumidifier of claim 1, wherein the main water reservoir includes ashut-off device.
 12. humidifier comprising: a housing; a main waterreservoir within the housing open to atmospheric pressure that isfinable by providing water through an opening in a top portion of thehousing; an engine deck disposed within the housing and configured tohold water, the engine deck being disposed above a bottom of the mainwater reservoir; a water feature disposed above the main water reservoirand configured to direct water to an overflow chamber of the enginedeck; an impeller configured to pump water from the main water reservoirto the water feature; an engine chamber disposed adjacent the main waterreservoir and below the engine deck, the engine chamber including atleast one motor for driving the impeller and a fan, the fan beingconfigured to generate an air flow over the engine deck and out of thehousing; and a humidification device disposed on the engine deck andconfigured to dissipate water into the air flow.
 13. The humidifier ofclaim 12 further comprising a control device operable to adjust the flowrate of the impeller.
 14. The humidifier of claim 12, wherein thehumidification device includes an ultrasonic nebulizer.
 15. Thehumidifier of claim 12, further comprising a cover configured to allowair and water to pass therethrough disposed over the engine deck, andstones disposed on the cover.
 16. A humidifier comprising: a housing; amain water reservoir within the housing open to atmospheric pressurethat is finable by providing water to an opening in a top portion of thehousing; a fan configured to generate an air flow through the housing;an impeller configured to pump water toward a top of the humidifier;17-26. (canceled)
 27. The humidifier of claim 16 wherein the impellerpumps water to the water feature, the humidification device includes awicking filter disposed beneath the water feature, and the water featureincludes at least one opening for supplying water to the wicking filter.28-29. (canceled)
 30. A humidifier comprising: a housing; a main waterreservoir within the housing open to atmospheric pressure that istillable by providing water through an opening in a top portion of thehousing; a fan configured to generate an air flow through the housing; awicking filter disposed above the main water reservoir and configured todistribute water into the air flow, the wicking filter beingsubstantially planar and inclined from which excess water drips in acontrolled manner into a conduit; an impeller configured to pump waterto a water feature disposed above the main water reservoir, the waterfeature configured to drip a portion of the pumped water onto thewicking filter and to direct at least a portion of the pumped water backto the main water reservoir, the water feature including a downwardcurved slope and a funnel at a bottom of the slope; and at east onemotor for driving the impeller and the fan.
 31. The humidifier of claim30 further comprising a control device operable to control a flow rateof the impeller.
 32. The humidifier of claim 30 wherein the wickingfilter is disposed on a v-shaped support that forms a lowest point at abottom of the v-shape.
 33. The humidifier of claim 32, wherein thev-shaped support includes a mesh support.
 34. The humidifier of claim33, wherein the conduit is disposed beneath the bottom of the v-shapedsupport.
 35. The humidifier of claim 30, wherein the wicking filter isdisposed on a mesh support.
 36. A humidifier comprising: a housing; amain water reservoir within the housing open to atmospheric pressurethat is fillable by providing water through an opening in a top portionof the housing; a fan configured to generate an air flow through thehousing; a wicking filter disposed above the main reservoir andconfigured to distribute water into the air flow; an impeller configuredto pump water to a water feature disposed above the main waterreservoir, the water feature configured to drip a portion of the pumpedwater onto the wicking filter and to direct at least a portion of thepumped water back to the main water reservoir, the water featureincluding a channel and at least one divider defining first and secondconduits within the channel, wherein the first conduit is disposed belowthe second conduit such that a flow of water below a threshold volumeflows only through the first conduit while a flow of water above thethreshold volume flows through the first and second channel; and atleast one motor for driving the impeller and the fan.
 37. The humidifierof claim 36, wherein the channel includes a plurality of openings fordripping water onto the wicking filter.
 38. The humidifier of claim 37,wherein the first conduit includes a single opening for dripping wateronto the wicking filter and the second conduit includes a plurality ofopenings for dripping water onto the wicking filter.